Specific antisera directed against cAMP-dependent protein kinase subunits will be used to examine the interaction of cAMP with protein kinase and to measure protein kinase synthesis and turnover. We shall determine whether type I and II protein kinases are differentially activated by cAMP in vitro using purified enzymes and in vivo in response to hormone stimulation. Studies are also planned which will determine if the regulatory and catalytic subunits of protein kinase are synthesized in a coordinate manner or whether synthesis and degradation are under separate control. We will see if cAMP affects the production or turnover of protein kinase subunits. Differential activation of protein kinase isoenzymes will be monitored by immunoprecipitation of the regulatory subunit-cAMP complexes and by radioimmunoassay of total cytosolic kinase isoenzymes. Protein kinase synthesis and turnover will be measured by 35S-methionine incorporation into regulatory subunits. Protein kinase turnover will be analyzed by polyacrylamide gel electrophoresis of purified subunits.